Left-lateral sense offset of Upper Proterozoic to Paleozoic features across the Gobi Onon, Tost, and Zuunbayan faults in southern Mongolia and implications for other central Asian faults

Folded Basinal Compartments of the Southern Mongolian Borderland: A Structural Archive of the Final Consolidation of the Central Asian Orogenic Belt

“…Thus, the Gobi Altai region's poly-deformational history and associated syn-tectonic clastic sedimentation history has resulted in a complex compartmentalized crustal architecture with limited exposures of deformed Permian-Jurassic strata (Figure 16). Left-lateral strike-slip faults also cut the region during this stage and may cause some refolding of Permian strata [26]. Stage 3 involved diffuse crustal extension during the early-mid Cretaceous that created basin and range-type compartmentalized rift basins and deposition of widespread alluvial sediments that unconformably overlapped the older deformed Permian-Jurassic strata [30,34].…”

“…The tectonic explanation for the older north-south trending folds identified in this study is unclear because they predate the 90 • CCW rotation of the southern arm of the CAOB orocline and thus they would have originally formed in an east-west direction along a former north-south convergent boundary. Perhaps a better explanation is that the folds are related to left-lateral wrench-related deformation in southern Gobi Altai crust that was a result of oblique closure of the Paleo-Asian ocean along the Solonker Suture (cf., [26]). …”

“…Collision-related crustal shortening likely persisted into the Triassic [5,8,18]. It is proposed that CAOB terrane amalgamation in southern Mongolia throughout the Paleozoic occurred along a north-south oriented active margin and that the accreted terrane assemblage was subsequently oroclinally bent in a counterclockwise sense during the Permo-Triassic into an east-west orientation and cut by sinistral strike-slip faults in the Triassic-mid Jurassic [8,9,24,26,27]. The terrane amalgamation history of southern Mongolia and the Beishan region imparted a dominant east-west structural grain throughout the region (modern coordinates) consisting of terrane boundaries (including suture belts), other faults, metamorphic foliation and sedimentary strike belt trends, and magmatic arc trends [4,8,9,28].…”

Surface deformations from moderate-sized earthquakes in Mongolia observed by InSAR

“…Therefore, data from this region are considered to have important implications for understanding the complex history of intracontinental deformation in Asia (Graham et al, 2001;Webb and Johnson, 2006). The Züünbayan and North Züünbayan faults, which are collectively referred to in some literature as the Züünbayan Fault Zone (ZBFZ) (Lamb et al, 1999), or the East Mongolian Fault Zone (EMFZ) (Yue and Liou, 1999), or the East Gobi Fault Zone (EGZF) (Webb and Johnson, 2006), follows the southern edge of the Altaid complex (Sengör et al, 1993) running along the EGB, and defines a structural corridor in this region. Yue and Liou (1999) and Lamb et al (1999) proposed a kinematic linkage between the EGFZ and the Altyn Tagh fault through the Alxa fault, just south of the MongoliaChina border.…”

“…The Züünbayan and North Züünbayan faults, which are collectively referred to in some literature as the Züünbayan Fault Zone (ZBFZ) (Lamb et al, 1999), or the East Mongolian Fault Zone (EMFZ) (Yue and Liou, 1999), or the East Gobi Fault Zone (EGZF) (Webb and Johnson, 2006), follows the southern edge of the Altaid complex (Sengör et al, 1993) running along the EGB, and defines a structural corridor in this region. Yue and Liou (1999) and Lamb et al (1999) proposed a kinematic linkage between the EGFZ and the Altyn Tagh fault through the Alxa fault, just south of the MongoliaChina border. Both define the EGFZ as a left-lateral strikeslip fault, but differ in the offset and the timing: ∼400 km offset in Cenozoic and ∼200 km offset mainly in Mesozoic, respectively.…”